Tests For Hearing
In infant most sensitive audiometric screening is:
|C||Cortical evoked response audiometry|
Methods of hearing assessment in infants and children... Dhingra 5th/131, 6th/ed p 118
• Neonatal Screnning Procedure:
o Arousal response cradule
• Behavior Observation Audiometry
o Moro's reflex
o Cochleopapebral reflex
o Cessation reflex
• Distraction techinques
• Condition techniques
o Visual reinforcement audiometry
o Play audiometry
• Objective tests
o Impedence audiometry
Screening the Newborn for Hearing loss
- Screening newborn for hearing loss leads to earlier detection and intervention in patients with congenital hearing impairment.
- Early intervention can improve speech and language development, and educational achievement in affected patients.
Screening Tests for hearing loss
Auditory Brainstem Response (ABR/BERA)
• Measures the summation of action potential from the 8th cranial nerve (cochlear nerve) to the inferior colliculus of the midbrain in response to a click stimulus.
• Non-inasive technique to find the integrity of central auditory pathways through the 8th cranial nerve. pons and midbrain.
• Delayed or absent waves suggest a neurologic or cochlear deficit
• Takes more time
• Child should be sedated
Otoacoustic Emissions (OAE)
• OAEs are low intensity sounds produced by outer produced by outer hair cells of a normal cochleA.
• OAEs are present when outer hair cells are healthy and are absent when they are damageD.
• Help to test the function of cochleA.
• Do not disappear in 8th nerve pathology as the cochlear hair cells are normal.
• OAE helps to distinguish cochlear from retrocochlear hearing loss
• Takes less time
• Sedation not requireD.
Thus both ABR-(or BERA) and OAE are used as a screeninq proceduce in infants and newborn for hearing loss. In Qs 31 and 32 there is no doubt as only BERA is given in options. Q 30 asks the screening procedure of choice and both OAE and BERA are given in options. Nowhere it is mentioned which is the initial screening procedure of choice.
As such, OAf testing is commonly used in newborn hearing screening because ofits speed and non invasive nature ... COGDT 3/e, p 625
• Infants who fail a screening test, require additional audiologic evaluation.
• In infants <8 months of age should be referred for diagnostic ABR/BERA.
• Hearing loss should be confirmed by visual reinforcement audiometry (VRA), when VRA can be performed reliably (>8 months of age).
• Visual reinforcement audiometry (VRA) is the gold standard/Investigation of choice for hearing assessment for non-verbal children.
• If VRA is not given in options or in infants <8 months (even is premature infants) and mortally retarded people: Investigation of choice is BERA.